Gravity-escapement for clocks



' (No Model.)

J. H. GERRY. GRAVITY BSGAPBMENT FOR CLOCKS.-

Patented July 3, 1883...

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UNITED ISTATES d PATENT I)metce..v

JAMES H. GERRY, OF SOMEEVILLE, MASSACHUSETTS.

GRAVITY-'ESCA'PEMENT FOR CLOCKS.

SPECIFICATION forming part of Letters Patent No. 280,463, dated July e, 1883,

y Application filed November 11K. 1882. (No model.)

T0 all whom it may concern vBe it known that I, J AMES H. GERRY, of Somerville, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Clock Escapements, of which the following is a specification.

This invention relates to that class of escapements known as gravity-escapements, in which the impulse is given to the pendulum and the escape-wheel unlocked by the .power of gravity. The most successful in this class of escap ements have been the three, 7 four, and double-three 7 arm escapements, all of which require an extra pinion and arbor, on which are thelocking-arms and fly. This additional pair of pivots at the extreme end of the train in` creases the resistance and friction, and calls for a very much heavier weight' to run the clock, which, besides being cumbersome, wears away the moving parts rapidly.

In my improved escapement I dispense with the extra pinion and place the escape-wheel on the fourth7 or minute arbor, the wheel being cut with the requisite number of teeth to give the required beats, (in this instance sixty teeth giving one hundred and twenty beats per minute,) I divide the gravity-arms into two distinct parts or levers-viz., the detent-arm and the impulse-arm-both of which move on the same center, as below described, the impulse-arm being lifted by means of a small lever attached to the detent-arm, which, acting for a short distance across the lines of centers-a1 e., a line drawn from the arbor of the escape-wheel to the pivot of said lever, and a linedrawn from the pivot of the lever to the fulcrum of the gravityarms, reduces the sliding friction (between the lever and impulse-arm and the lever and escape-wheel) to a minimum. Thus the weight may be reduced to just enough to keep the pendulum in motion and absolute safety from tripping is secured, while the adjustment may be to a nicety.

In the accompanying drawings, in which similar letters of reference indicate like parts, Figure l is a front elevation of the front plate of a clock provided with my improved escapement. Fig. 2 is an enlarged view of the working parts of the same, with the pendulum and bridges removed. Fig. 3 is aside elevation of the device. Fig. 4 is a vertical section on line a; m, Fig. 2. f Fig. 5 is a horizontal section on Fios. 2 4 and 5 are all cnl saidarbors D D. Thus it will be seen that the diameters of the bearings ofthe detent-arms and impulse-arms are the same. These arbors D D are straight pieces of wire, and the detent-arms can end-shake7 with the arbors between the plate A andthe sleeves f f, while the sleeves can end-shake between the hubs of the detentarms and the bridge a. Each pair or set, consisting of a detentarm and impulse-arm, takes the place of a single gravity-arm,as is now com-v mon. The detent-arms H H bank upon the pins h h, projecting from the plate A, and are bent back upon themselves at H2, so as to provide for pivots g g for the levers I I', having suitable hubs, Il, Fig. 5. The levers I I are provided with lifting-pins J J acting on the impulse-arms,and detents K K,acted upon by the teeth of the escape-wheel. The detent-arms H H are provided with the banking-pins L L below the levers I I, and banking-pins P P above the levers. The lifting arms or pins J J may be bent up from the levers I I or pins rigidly secured therein, as desired. The one lettered J is made by the former, and that lettered J by the latter, method. The impulsearms F E are slightly curved to accommodate the pivots g g of the levers I I. In the drawings, the pendulum-rod E is represented as having swung from the detent-arm H, and, followed by the impulse-arm F, is about to lift the detent-arm H and impulse-arm F. It is of such shape as to reach them at the same time, and when said arms E H are lifted the detent K leaves the escape-wheel and the banking-pin L and banks against the pin 1),.the escape-wheel moves one-half a space between teeth, carrying with it the lever I by means of its detent K', and the lifting-pin J raises the im- IOO pulse-lever F, which remains raised until the pendulum has completed its stroke. The lever l banks as it rises and falls against the pins 1)/ and L, and the lever I, by means of its detent K, against the pins P and L. The impulse-lever can be raised without the intervention oi' the lever l by constructing a lifting angle on the impulse arm or lever, and making the detent integral with or rigidly secured to the detent-arm. But the construction described is preferable, as the great sliding frietion between such an angle and the teeth of the escape-Wheel is avoided.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In a elock-escapement, a gravity-arm substantially as shown, divided into two distinct parts, one of said parts being adapted to act as a detent and the other as an impulse arm, said detent portion being constructed and adapted, as shown, to fall into position by the power of gravity and lock the eSCapeWheel, substantially as and for the purpose set forth.

2. Inaelock-escapement, a gravityarm substantially as shown, divided into two distinct parts, one of said parts being adapted to act as a detent and the other as an impulse arm, said land for the purpose set forth.

4. The combination ofthe plate A, arbor D, placed loosely therein, detent-arm H, rigidly secured to said arbor, and i1npulse-ar1nF,xed to the sleeve f,placed loosely on said arbor, arranged and constructed substantially as and for the purpose described.

5. The combination of the impulse-arm F and detent arm H, provided with lifting-pin J, banking-pins L P, and lever I, the escape-wheel C, and the impulsearm F and detent-arm H, provided with lifting-pin J, banking-pins I/ P, and lever I', all arranged and constructed substantially as and for the purpose set forth.

' JAMES H. GERRY.

W'itnesses:

HENRY W. WILLIAMs, JOSEPH IsHBAUG-H. 

